title: Early social deprivation impairs pair bonding and alters serum corticosterone and the NAcc dopamine system in mandarin voles.
abstract: Early life stress has a long-term negative impact on emotion, learning, memory and adult sexual behavior, and these deficits most likely impair pair bonding. Here, we investigated whether early social deprivation (ED) affects the formation of pair bonds in socially monogamous mandarin voles (Microtus mandarinus). In a partner preference test (PPT), ED-reared adult females and males did not show a preference for their partner, spent more time exploring the cage of an unfamiliar animal and directed high levels of aggression toward unfamiliar animals. In social interaction test, ED increased exploring behavior only in females, but increased movement around the partner and reduced inactivity in both males and females. Three days of cohabitation did not alter serum corticosterone levels in ED-reared males, but increased corticosterone levels in males that received bi-parental care (PC). Interestingly, serum corticosterone levels in ED- and PC-reared females declined after cohabitation. ED significantly increased basal serum corticosterone levels in males, but had no effect on females. ED significantly up-regulated the levels of dopamine and the mRNA expression of dopamine 1-type receptor (D1R) in the nucleus accumbens (NAcc) in females and males. ED suppressed dopamine 2-type receptor mRNA (D2R) expression in females, but increased this in males. After three days of cohabitation, levels of D1R mRNA and D2R mRNA expression changed in opposite directions in PC-reared voles, but in the same direction in ED-reared males, and only the expression of D2R mRNA increased in ED-reared females. Our results indicate that early social deprivation inhibits pair bonding at adulthood. This inhibition is possibly associated with sex-specific alterations in serum corticosterone, levels of dopamine and mRNA expression of two types of dopamine receptors in the NAcc.
authors.affiliation: Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an 710062, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Yu
authors.forename: Shucheng
authors.initials: S
authors.lastname: An
authors.forename: Fadao
authors.initials: F
authors.lastname: Tai
authors.forename: Jianli
authors.initials: J
authors.lastname: Wang
authors.forename: Ruiyong
authors.initials: R
authors.lastname: Wu
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000502:physiology*; D001522:Behavior, Animal; D003345:Corticosterone / Q000097:blood*; D004298:Dopamine / Q000502:physiology*; D005260:Female; D007398:Interpersonal Relations; D008297:Male; D052586:Mating Preference, Animal; D017551:Microdialysis; D009714:Nucleus Accumbens / Q000502:physiology*; D010152:Pair Bond; D017447:Receptors, Dopamine D1 / Q000096:biosynthesis / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000096:biosynthesis / Q000378:metabolism; D012727:Sex Characteristics; D012934:Social Isolation / Q000523:psychology*
chemical_list: D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D004298:Dopamine; D003345:Corticosterone
keywords: Corticosterone; Dopamine system in the NAcc; Early social deprivation; Mandarin vole (Microtus mandarinus); Pair bonding